(CNN) — Philippine ships have been allowed to access the contested Scarborough Shoal in the South China Sea, with Chinese ships not harassing Filipino fisherman for the first time in years.

Philippines Defense Secretary Delfin Lorenzana told CNN Monday that aerial surveillance had shown that Chinese patrol boats were still guarding the small but strategic reef, but had allowed Filipino boats to enter and fish in the nearby waters.

"They are still there, but they are not harassing or preventing our fishermen from fishing," he said.

"This is a welcome development for our fishermen who have been forcibly prevented to fish in their traditional fishing ground," he added.

The apparent concession from Beijing is a victory for President Rodrigo Duterte in a long-running territorial dispute in the South China Sea.

Duterte visited China earlier this month and has, controversially, charted a foreign policy that eschews its traditional ally, the United States.

On Friday, China's Foreign Ministry spokesman said that ties between the two countries had entered "a stage of improvement" and said both sides were in communication over the South China Sea.

"This is the most important gain of the President's visit to China and proof that the President's pivot to Asia has been successful in promoting the right of our fishermen to pursue their traditional livelihood," said Harry Roque, a congressman who accompanied Duterte on his trip to Beijing.

Tensions first flared at the Scarborough Shoal in 2012 when China effectively evicted Filipino fishermen from the area, souring relations between the two countries.

In July, a landmark international tribunal ruled against China's claims in the South China Sea and said they had unlawfully restricted fishing access to the maritime feature.

However, since taking office Duterte has pushed the issue to the background and tried to forge closer ties with China and, explosively, threatening to "separate" militarily and economically from the US.

During his trip, Duterte signed 13 deals including pacts on trade, tourism, investment and drug prohibition.

"These developments suggest that China is serious about making partial South China Sea compromises to improve its relationship with the Philippines at America's expense," said Ashley Townshend, a research fellow at the United States Studies Centre at the University of Sydney

Analysts have described the Scarborough Shoal as a strategic foothold for China, but the latest development suggests that Beijing won't reclaim land at the reef as some have feared, Townshend added.

Just 130 miles (about 209 km) from the Philippines, the reef, which is a fertile fishing ground, is in within range of Subic Bay, a former American military base that US Marines, ships and planes have resumed using again under a new deal.

China claims almost all of the South China Sea, including islands more than 800 miles (1,200 kilometers) from the Chinese mainland, despite objections from neighbors including the Philippines, Malaysia, Brunei and Vietnam.

Tensions have ratcheted up in the past two years as China has reclaimed land in massive dredging operations in the Spratly Islands, turning sandbars into islands equipped with airfields, ports and lighthouses.

In recent months, Beijing has reacted angrily to US freedom of navigation operations in the region, scrambling fighter jets and boats and denouncing the nation's navies as "threatening Chinese sovereignty."